Planetary Surfaces


The goals of the studies in the topic « Planetary Surfaces » are the observation and interpretation of Earth and planetary processes including erosion, volcanism, tectonism, alteration, sedimentation, etc. We take part in many planetary missions (toward Mars, icy satellites, Pluto, Venus) and are involved as well in terrestrial aerial and orbital instruments. Our main means consist of a computer platform for remote sensing processing (optical, IR and topographic data), laboratory instruments for petrological and geochemical analyses (microscopes, alteration reactors, etc.) and hyperspectral instruments (both for field or lab) that help to validate remote sensing data by measuring spectra of natural or synthetic samples.



Mars geology

Several studies focus on the analysis of Mars surface from orbital data, including fluvial, eolian and glacial landforms, coupling optical, IR and topographic data from Mars Express instruments OMEGA and HRSC. Our results show the occurrence of ice deposits outside the polar caps, the decrease of the fluvial activity through time, the ubiquity of hydrous minerals on old terrains, and their correlation with hydrothermal or climatic processes depending on locations, in connection with lab analyses of experimental alteration. A new type of studies in our lab consists of the in situ analyses from the Curiosity rover instruments. Results obtained are complementary to orbital data analyses showing the presence of a past lake as well as a more siliceous composition of the Mars crust. This last point if connected to the study of Martian meteorites, for which the most recent finding correspond to a piece of breccia from the ancient crust.




Titan and icy satellites exploration

Titan is a satellite from Saturn with very specific surface conditions (atmospheric pressure of 1.5 bar, Temperatures of -180°C) that allow methane and other organic compounds to be liquid. Thanks to collaboration with the Cassini mission team, studies done at LPG have contributed to the understanding of Titan methane lakes evolution, the role of dissolution and the seasonal evolution of clouds. In addition our contributions to the surface of icy bodies include lab analyses of icy materials and participations in the missions New Horizons to Pluto and JUICE to Jupiter satellites.




Earth as reference

Better understand the Earth helps to understand planetary processes. Our activities focus on studies centered on specific terrestrial processes, especially on terrestrial analogues. Field works are achieved in Namibia, Marocco, Iceland, Ethiopia or Indonesia, and are complemented by lab analyses, spectral data acquisition, analogic or numerical modeling. These works focus on mineralogical processes (weathering, opal crystallization, mining waste, etc.), sedimentary processes (coastal zone evolution) or geodynamical processes (vertical movements, fluid circulation, crustal intrusions). New collaborations with associates at Le Mans will help to develop these objectives using analog modeling on specific processes linked to fluids and deformation.